Recovery of wax from oils



Aug. 9, 1932. GRAVES 1 ,871,172

' RECOVERY OF WAX FROM OILS Original Filed Aug. 20, 1926 Gear 6 J620066, WW%

' P tented Au 9,1932

- UNITED TATES PATENT OFFICE GEORGE D. GRAVES, OF CASPER, WYOMING,ASSIGNOB TO STANDARD OIL comm,

' OF WRITING, l OOB POBATION OI INDIANA RECOVERY OI WAX II ZBDI OILSApplication filed August e0, 1928, Serial no. 136,444. mm; an 29, mo.

This invention relates to therecovery of wax from oils containingrelatively large proportions of wax, for example, foots oil.

According to the present invention, foots '5 oil or similar oil iscooled below its chill point, while subjecting to 'agltatlon, a finegrained mushy mass belng produced. A

, temperature in the neighborhood of 7 6 F., for example, between 63 and73 1s suitable "1c in the case of foots oil. This mass is impregnatedwith air or other suitable gas so that small gas bubbles are dispersedthroughout the mass and while in this condition, it is filtered. Thistreatment with gas may be effected simultaneously with or subsequent tothe chilling. A rotary filter of the drum type is preferred since themass is more rapidly handled and the gas bubbles have less opportunityto segregate. Good results may, however, be obtained by orfhnaryfilter-presses. Filtration yields a porous cake of wax from which theoil is readily removed. The cake thus produced contains a -largepercentage of wax and is suitable-for sweating, giving dry wax inquantity about double that which could be obtained by sweating the footsoil..

The accompanying drawlng 1llustrates an apparatus suitable for carryingout the mproved method, the chiller-mixer being shown in section and thefilter diagrammaticall T he invention will readily be understood fromthe following example.

Foots oil containin 52.6% of oil and having a melting point 86 F. waschilled to 65 F. with thorough agitation and mjection' of air so as toreduce a fine, aerated mushy mass. The chilled aerated mushy mass wasthen filtered in an Oliver or drum type rotary filter, giving a porouscake which separated cleanly from the blanket. This wax contained 21.6%of oil; its melting point was 104 F. and in amount it corresponded to32% of-the foots oil and contained 53% of the wax in the original footsoil. This wax was sweated at 110 F. for hours andielded a wax containing0.5%of oil and aving a melting point of 118 The 50 amount of wax was13.0% of the original foots oil. In comparison, it may be stated that bydirect sweating of foots oil, only 6.9% of' high melt point wax wasobtained and, moreover, the sweating of foots oil is very tedious sinceslow sweating is necessary. Referring to the accompanying drawing, 10 isa chiller-mixer comprising a vertical tank divided into two superimposedcompartments 11 and 12 which are separated by a perforated partition 13.The compartments 11 and 12 are provided with cooling p ckets 14 and 15,preferably connecting through pipe 16, the upper cooling jacket 14 beingprovided with an inlet 17 for the cooling medium and the lower coolingjacket being provided with an outlet 18 for cooling. medium. The lowercompartment 12 is provided near its bottom with an oil inlet pipe 19 andthe upper compartment 11 is provided in its upper portion with an oiloutlet pipe 20 which leads the mushy mass to the filter 21. Thecompartments 11 and 12 are provided with effective agitators which maysuitably be vanes 22 mounted on a shaft 23 which extends through the topof the chiller-mixer and throu h the perforated partition 13 and isprovide with suitable bearings 24 and 25 in the top and bottom of thechiller-mixer. The stem 23 is provided with any suitable driving gear.such as the pulley 26. The vanes 22 are preferably arranged to scrapethe internal walls of the compartments 11 and 12, thereby ensuring moreuniform cooling and a finer mushy mass. Above the perforated partition13, an air pipe 27 passes into the compartment 11, said pipecommunieating with an annular pipe 28 provided with perforations 29directed upwards. The filter 21 diagrammatically shown, comprises atrough 30 and a rotating drum 31, the cylindrical surface of which isprovided with filter bianket. The drum is divided internally intocompartments communicating through the hollow trunnion and throughsuitable valves to exhausting and pressure pumps so that vacuum isapplied to the submerged portion of the drum for the purpose of liftinga layer of wax, and pressure is applied in the upper portion of thedrum, so as to detach the layer from the blanket, so that it can readilybe said suspension to separate the suspended removed by the scraper 32.A detailed description of this filter is considered unnecescontinuouslythrough pipe 19 to the -co'm- 1 partments 12 and i1 and thence to thefilter 21 through pipe 20. The stirrer vanes 22 are set in rotation,cooling medium is supplied to the coolin ackets 12, and 15 by air issupp 1ed by pipe 27.

The cooling is regulated so that the desired filtering temperaturedwhich may be around 70 is obtains The stirring should be sufiicientlyvigorous to yield a fine mush mass.

I c aim:

L The .method of recovering wax from foots oil which consists inchilling the oil to about 63 to 7 3 l b, injecting inert gas there-.into andagitating so as to produce a fine mushy mass having small asbubbles distributed therethrough and fi tering the mass while the gasbubbles are thus distributed.

2. The method of recovering wax from foots oil which consists in coolingthe oil below its chill point, injecting inert gas thereinto andagitating so as to produce a fine mushy mass having small as bubblesdistributed therethrough, an filtering mushy mass while the bubbles arethus distributed.

3. The method of recovering wax from h drocarbon oil, which consists incooling t e oil containing a substantial pro ortion of wax below itschill point while in ecting inert gas thei einto, thereby producing amushy mass of oil and wax havmg small gas bubbles dispersed therethroughand U filtering the mush mass while in that condition.

4. he method of recovering wax from foots oil which comprises, coolinthe oil below its chill point; agitating the 01 to form it into a mushysuspension of wax and oil, whereby the physical structure of the wax isbroken down'and the wax and oil are easily separable, and filtering thesuspension to separate the suspended wax from theoil.

5. The method of recovering wax from foots, oil which comprises, coolinthe oil below its chill .to form a mus y suspension of wax and oil thesuspended wax bein distributed throughout the Oil body, an filtering thewax .from the oil.

GEORGE D. GRAVES.

pipe 17 and thepoint, agitating the c 'lled oil 7

